Junos OS


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Multiple DHCP pools for auto-configured subscribers' interfaces

  • 1.  Multiple DHCP pools for auto-configured subscribers' interfaces

    Posted 07-30-2021 13:41
    Hi Jiniper community,
    Looking for a way to provide IP addresses via DHCP to relatively big number of subscribers with vlan-per-customer model. Subscriber interfaces are created dynamically with auto-configure first for VLAN demux and second for IP demux with DHCP. If I understand correctly, DHCP needs to match the network configured in the DHCP pool with unnumbered IP assigned to a demux interface. How can it be handled if I have multiple discontinuous IP subnets for DHCP pools, let's say two completely different /24, and assign IPs from them to subscribers coming from the same physical interface, let's say ae0. Should I assign an IP from each pool to lo0.0 to use it as unnumbered for subscribers? How interface IP will be selected in this case, in relation to preferred address?
    For PPPoE I can link pools and use unnumbered address that's not related to the pool range because it's actual P2P. Is there a workaround for that for DHCP?


  • 2.  RE: Multiple DHCP pools for auto-configured subscribers' interfaces

    Posted 08-03-2021 19:58
    Seems like I found the solution myself with try-and-fail method. For DHCP subscribers, pools can be linked like for PPPoE (not sure if it's really necessary but it works) and IP from each pool's network have to be configured on lo0.0. So, if there are many disaggregated subnets in network pools, lo0 has to hold many secondary addresses. Therefore it's preferable to have big pools (as big as possible) to avoid configuring too many IPs on lo0.